Reaction product of mercaptothiazole and alpha schiff&#39;s base and method of producingsame



Patented May 6, 1930 UNITED STATES PATENT OFFICE Loam B. snBnnnL, or AKRON, 'oHIo, assrenon TO THE eoonxma-rmn & RUBBER comm, or AKRON, OHIO, A conronnrron or cure REACTION PRODUCT 01 MERCAPTOTHIAZOLE AND A SCHIFFS BASE AND METHOD OF PRODUCING SAME No Drawing. Original application filed September 13, 1927, Serial No. 219,365. Divided and this application filed. June 16,

My invention relates to the treatment of rubber and it has for its primary object the provision of a desirable material for accelerating the vulcanization of rubber products.

More specifically my invention has for one of its objects the provision of an accelerator which is composed of the reaction products of a mercaptothiazole and an aldehyde amine condensation product.

This application is a division of application Serial No. 219, 365, filed September 13, 1927.

It has previously been known that mercaptothiazoles were powerful accelerators of the vulcanization of rubber products. It has also been known that the mercaptothiazoles might be caused to react with other substances, such as metallic salts, aldehydes, ammonia and amines, to produce accelerators which were, in many cases, superior to the mercaptothiazoles from which they were derived.

T have made the discovery that mercaptothiazoles, such as mercaptobenzothiazoles, may be caused to react with aldehyde amine condensation products, known as Schifl bases,

to produce accelerators having very desirable properties. The general formula of a Schifi base is represented as follows:

The radicals indicated by the characters R and R may be either straightchain or cyclic hydrocarbons.

This class of compounds includes the reaction products of crotonaldehyde and aniline, (crotylidene aniline), acetaldehyde and aniline (ethylidene aniline), crotonaldehyde methylamine, propyl aldehyde and ethylamine, butyl aldehyde, aniline, butyl aldehyde toluidine, heptaldehyde aniline, heptaldehyde butyl amine, aniline cinnamic aldehyde, and numerous other hydrocarbon compounds which include the grouping indicated in the formula.

A specific example of a compound which falls within the scope of my invention is the crotonaldehyde aniline mercaptobenzothia- Sulphur 1928. Serial No. 286,072.

zole reaction product. This material may be prepared as follows:

Intermix molecular' quantities of the mercaptobenzothiazole and the crotonaldehyde aniline reaction products, and reflux them for a period of two hours or more. An exothermic reaction takes place during this period. Also, water and hydrogen sulphide are given off, as is evident from the odorand the appearance of the condensate. The product obtained is a thick semi-solid which may be hardened to a resin-like state by distilling ofi a little aniline. The chemical formula of the reaction product is unknown. It is to be understood that this method of preparing the reaction product of the ,mercaptothiazole and the Schifi' bases is of general application, and may be employed to manufacture various other materials of this class, which have been mentioned.

The material prepared according to the above described method may be incorporated into various rubber compounds. The following is a sample formula of a compound which insures excellent results:

Parts Pale crepe rubber 100 Zinc oxide 5 3 1.5 .5

Stearic acid Accelerator The accelerative properties of the material prepared according to the method discussed were tested in the above formula and the results obtained are tabulated in the following tables.

TABLE I Mereaptobmzothiczole control Cum Tensile Percent strength along. at kga/cm' break 500% elong. kga/cm' Time in mim- Pressure ease Essa

TABLE II Crotyltdem aniline control CrotonaZdehydeAnilinc-Mcrcaptobenzothia zole um 500% 700% Tensile Percent elong. elong. strength elong. Tgpigsm Pressure kgs/cin kgs/cm kgs/cm at break 7 TABLE IV M crcaptobenzothiozolc solid ethylidcne aniline Cure 500% 700% Tensile Percent elong. elong. strength elong. Tune in Pressure kgs./em kgs./cm kgsJcni at break mlns.

Tables I and II, respectively, contain data obtained by testing samples in which the pure mercaptobenzothiazole and crotylidene aniline were used as accelerators. Table III contains data obtained from tests conducted upon samples containing the reaction product I of mercaptobenzothiazole and the crotonaldehyde aniline condensation product. Table IV contains data obtained from the testing of rubber samples containing the reaction products of mercaptobenzothiazole and ethylidene aniline. Comparison of the data contained in Tables I and II with that contained in Tables III and IV clearly indicates that the reaction products of the mercaptothiazoles and the Schitl bases are materially more powerful accelerators than either mercaptothiazole or crotylidene aniline alone.

Since the product resulting from the combination of the thiazole and the Schifls base is a more powerful accelerator than either of the original compounds, it is evident that a true chemical reaction takes place. The latter fact may be further demonstrated by extracting the final product with an alkali. The latter treatment would remove any unreacted mercaptoben zothiazole in its original state. Since no free m'ercaptobenzothiazole is thus obtained, it is clear that it has combined with the Schifis base.

Although I have disclosed only 'the preferred embodiments of the invention and described those embodiments in detail, it will be apparent to those skilled in the art that the invention is not so limited, but that various minor modifications may be made therein without departing from the spirit of the invention or from the scope of the appended claims.

What I claim is:

1. A method of producing a rubber vulcanization accelerator which com rises refluxing a mercaptothiazole and a chiff base for a period of approximately two hours.

2. A method of producing a rubber vulcanization accelerator which comprises refluxing molecular quantities of a mercaptothiazole and a condensation product of an aldehyde and an aromatic amine for a period of approximately two hours.

3. A method of producing a rubber vulcanization accelerator which comprises refluxing molecular quantities of a mercaptothiazole and ethylidene aniline for a period of approximately two hours.

4. A new compound comprising a reaction product of mercaptobenzothiazole and ethylidene anlline.

5. A method of producing a rubber vulcanization accelerator which comprises refluxing a Schifi? base formed by the interaction of a primary aryl amine containing a single benzene nucleus, with an aliphatic aldehyde and.mercaptobenzothiazole until a reaction product is formed.

6. A method of producing a rubber vulcanization accelerator which comprises refluxingmercaptobenzothiazole with a Schifi base formed by the interaction of aniline with an aliphatic aldehyde.

7. A method of producing a rubber vulcanization accelerator which comprises refluxing mercaptobenzothiazole with a Schifl base formed by the interaction of a primary aromatic amine with an aliphatic aldehyde.

8. A new compound comprising a reaction product of mercaptoben zothiazole with a Schifi' base formed by the interaction of a primary aromatic amine containing a single benzene nucleus andan aliphatic aldehyde.

In witness whereof, I have hereunto signed my name.

Signed at Akron, in the county of Summit, and State of Ohio, this 11th day of June, 1928.

LORIN B. SEBRELL. 

